i2pd/aes.h

#ifndef AES_H__
#define AES_H__

#include <inttypes.h>
#include <cryptopp/modes.h>
#include <cryptopp/aes.h>
#include "Identity.h"

namespace i2p
{
namespace crypto
{	
	union ChipherBlock	
	{
		uint8_t buf[16];
		uint64_t ll[2];

		void operator^=(const ChipherBlock& other) // XOR
		{
			ll[0] ^= other.ll[0];
			ll[1] ^= other.ll[1];
		}	 
	};

	typedef i2p::data::Tag<32> AESKey;
	
	template<size_t sz>
	class AESAlignedBuffer // 16 bytes alignment
	{
		public:
		
			AESAlignedBuffer ()
			{
				m_Buf = m_UnalignedBuffer;
				uint8_t rem = ((uint64_t)m_Buf) & 0x0f;
				if (rem)
					m_Buf += (16 - rem);
			}
		
			operator uint8_t * () { return m_Buf; };
			operator const uint8_t * () const { return m_Buf; };

		private:

			uint8_t m_UnalignedBuffer[sz + 15]; // up to 15 bytes alignment
			uint8_t * m_Buf;
	};			


#ifdef AESNI
	class ECBCryptoAESNI
	{	
		public:

			uint8_t * GetKeySchedule () { return m_KeySchedule; };

		protected:

			void ExpandKey (const AESKey& key);
		
		private:

			AESAlignedBuffer<240> m_KeySchedule;  // 14 rounds for AES-256, 240 bytes
	};	

	class ECBEncryptionAESNI: public ECBCryptoAESNI
	{
		public:
		
			void SetKey (const AESKey& key) { ExpandKey (key); };
			void Encrypt (const ChipherBlock * in, ChipherBlock * out);	
	};	

	class ECBDecryptionAESNI: public ECBCryptoAESNI
	{
		public:
		
			void SetKey (const AESKey& key);
			void Decrypt (const ChipherBlock * in, ChipherBlock * out);		
	};	

	typedef ECBEncryptionAESNI ECBEncryption;
	typedef ECBDecryptionAESNI ECBDecryption;

#else // use crypto++

	class ECBEncryption
	{
		public:
		
			void SetKey (const AESKey& key) 
			{ 
				m_Encryption.SetKey (key, 32); 
			}
			void Encrypt (const ChipherBlock * in, ChipherBlock * out)
			{
				m_Encryption.ProcessData (out->buf, in->buf, 16);
			}	

		private:

			CryptoPP::ECB_Mode<CryptoPP::AES>::Encryption m_Encryption;
	};	

	class ECBDecryption
	{
		public:
		
			void SetKey (const AESKey& key) 
			{ 
				m_Decryption.SetKey (key, 32); 
			}
			void Decrypt (const ChipherBlock * in, ChipherBlock * out)
			{
				m_Decryption.ProcessData (out->buf, in->buf, 16);
			}	

		private:

			CryptoPP::ECB_Mode<CryptoPP::AES>::Decryption m_Decryption;
	};		


#endif			

	class CBCEncryption
	{
		public:
	
			CBCEncryption () { memset (m_LastBlock.buf, 0, 16); };

			void SetKey (const AESKey& key) { m_ECBEncryption.SetKey (key); }; // 32 bytes
			void SetIV (const uint8_t * iv) { memcpy (m_LastBlock.buf, iv, 16); }; // 16 bytes

			void Encrypt (int numBlocks, const ChipherBlock * in, ChipherBlock * out);
			void Encrypt (const uint8_t * in, std::size_t len, uint8_t * out);
			void Encrypt (const uint8_t * in, uint8_t * out); // one block

		private:

			ChipherBlock m_LastBlock;
			
			ECBEncryption m_ECBEncryption;
	};

	class CBCDecryption
	{
		public:
	
			CBCDecryption () { memset (m_IV.buf, 0, 16); };

			void SetKey (const AESKey& key) { m_ECBDecryption.SetKey (key); }; // 32 bytes
			void SetIV (const uint8_t * iv) { memcpy (m_IV.buf, iv, 16); }; // 16 bytes

			void Decrypt (int numBlocks, const ChipherBlock * in, ChipherBlock * out);
			void Decrypt (const uint8_t * in, std::size_t len, uint8_t * out);
			void Decrypt (const uint8_t * in, uint8_t * out); // one block

		private:

			ChipherBlock m_IV;
			ECBDecryption m_ECBDecryption;
	};	

	class TunnelEncryption // with double IV encryption
	{
		public:

			void SetKeys (const AESKey& layerKey, const AESKey& ivKey)
			{
				m_LayerEncryption.SetKey (layerKey);
				m_IVEncryption.SetKey (ivKey);
			}	

			void Encrypt (uint8_t * payload); // 1024 bytes (16 IV + 1008 data)		

		private:

			ECBEncryption m_IVEncryption;
#ifdef AESNI
			ECBEncryption m_LayerEncryption;
#else
			CBCEncryption m_LayerEncryption;
#endif
	};

	class TunnelDecryption // with double IV encryption
	{
		public:

			void SetKeys (const AESKey& layerKey, const AESKey& ivKey)
			{
				m_LayerDecryption.SetKey (layerKey);
				m_IVDecryption.SetKey (ivKey);
			}			

			void Decrypt (uint8_t * payload); // 1024 bytes (16 IV + 1008 data)	

		private:

			ECBDecryption m_IVDecryption;
#ifdef AESNI
			ECBDecryption m_LayerDecryption;
#else
			CBCDecryption m_LayerDecryption;
#endif
	};
}
}

#endif